Sarez Lake is a lake in Rushon District of Gorno-Badakhshan province, Tajikistan. Length about 75.8 kilometres (47.1 mi), depth few hundred meters, water surface elevation about 3,263 metres (10,705 ft) above sea level and volume of water is more than 16 cubic kilometres (3.8 cu mi). The mountains around rise more than 2,300 metres (7,500 ft) above the lake level.

The lake formed in 1911, after a great earthquake, when the Murghab River was blocked by a big landslide. Scientists believe that the landslide dam formed by the earthquake, known as the Usoi Dam, is unstable given local seismicity, and that the terrain below the lake is in danger of catastrophic flood if the dam were to fail during a future earthquake.

Varzob is located on the left (east) bank of the Varzob River, about 25 km north of Dushanbe. The village of Begar lies about 2.5 km north of Varzob on the right bank of the river, and the village of Varzobkala lies just .75 km south of Varzob on the right bank of the river.